Characterisation of non-capsulate Haemophilus influenzae by repetitive extragenic palindromic (REP)-PCR

The use of repetitive extragenic palindromic (REP)-PCR to characterise non-capsulate Haemophilus influenzae (NCHI) for epidemiological studies was validated by application to four outbreak-associated and three epidemiologically unrelated NCHI strains of the same phenotype which had been well characterised by other methods. The REP-PCR patterns were reproducible and showed the unrelated isolates to be distinguishable from each other, whereas the outbreak-associated isolates were indistinguishable. The results were concordant with those from outer-membrane protein enriched profiles, ribotyping and randomly amplified polymorphic DNA analysis. When applied to six further isolates from two different suspected outbreaks, rapid results were obtained from boiled supernates prepared from one colony and indicated that the isolates in question were not related. REP-PCR provides a rapid method of strain characterisation suitable for NCHI, which is ideal for use in conjunction with other methods.